CA1144681A - Extruder grafting process for pvc impact modifier - Google Patents
Extruder grafting process for pvc impact modifierInfo
- Publication number
- CA1144681A CA1144681A CA000368891A CA368891A CA1144681A CA 1144681 A CA1144681 A CA 1144681A CA 000368891 A CA000368891 A CA 000368891A CA 368891 A CA368891 A CA 368891A CA 1144681 A CA1144681 A CA 1144681A
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- Prior art keywords
- monomer
- polymer
- ethylene
- zone
- initiator
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F255/00—Macromolecular compounds obtained by polymerising monomers on to polymers of hydrocarbons as defined in group C08F10/00
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L27/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers
- C08L27/02—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L27/04—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment containing chlorine atoms
- C08L27/06—Homopolymers or copolymers of vinyl chloride
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L51/00—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
- C08L51/06—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers grafted on to homopolymers or copolymers of aliphatic hydrocarbons containing only one carbon-to-carbon double bond
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Graft Or Block Polymers (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
PVC impact modifiers prepared by grafting, in a melt reaction, a monomer system comprising at least 50% by weight methyl methacrylate to a polymer of ethylene, exclusive of high density polyethylene, or a mixture of two or more such polymers. An extruder process for pre-paring the modifiers, and blends of the modifiers with polyvinyl chloride, are disclosed.
PVC impact modifiers prepared by grafting, in a melt reaction, a monomer system comprising at least 50% by weight methyl methacrylate to a polymer of ethylene, exclusive of high density polyethylene, or a mixture of two or more such polymers. An extruder process for pre-paring the modifiers, and blends of the modifiers with polyvinyl chloride, are disclosed.
Description
EXTRUDER GRAFTING PROCESS FOR PVC IMPACT MODIFIERS
BACKGROUND OF THE INV NTION
FIELD OF THE INVENTION
This invention relates to PVC impact modifiers, s their preparation, and use.
DESCRIPTION OF THE PRIOR ART
Conventional impact modifiers for PVC are multiple stage polymers having a butadiene or a methyl acrylate or ethyl acrylate first stage, and methyl methacrylate, acrylonitrile and/or styrene in one or more subsequent stages. U.S. Patents 2,892,809; 2,943,074; 3,251,904 are typical. Chlorinated polyethylene and ethylene-vinyl acetate have also been shown to be useful. See also Ency-clopedia of Polymer Science and Technology, under "Impact Resistance, PVC", and Plasty a Xaucuk 13, 129 and 193 (1976), and Plastics Technology, July 1975, page 48.
Each of these prior modifiers suffer from one or more disadvantages in the area of weatherability, ` impact efficiency, compoundability, processability into blends with PVC, and properties of blends with PVC.
, Steinkamp et al., U.S. Patent 3,862,265, show improvements to polyolefins in flow and adhesion by a controlled reaction often involving degradation in an extruder in which initiator is injected under conditions of either maximum distribution or intensive mixing wherein appreciable rheological, i.e. molecular weight distribu-tion, changes in said base polymer occur. In some ~ .
,s~ ~,, ~
11'~4~
embodiments monomers are also grafted during the degra-dation process. The extruder reactors shown by Steinkamp et al., have a first polymer addition and melting zone, a second zone for monomer and initiator addition and reaction, and a third zone for vacuum devolatilization and extrusion or removal of product. In the second zone, the mixing is under high intensity in a very short period of time. Materials can be added prior to the reaction zone, become mixed by extruder action, and thence con-veyed to the reaction zone where they are available toparticipate in the reaction. Steinkamp et al., does not show graft polymers which are useful as impact modi-fiers for PVC.
Nowak et al., U.S. Patent 3,177,269, teach an extruder grafting process using an olefinic polymer sub-strate and grafting thereto acrylic acid, methacrylic acids, or mixtures thereof. The graft polymer is recovered by use of an inert solvent, and is used as a molding resin.
Jones et al., U.S. Patent 3,177,270, teach a process similar to Nowak et al., supra, except using monovinyl aromatic compounds as the grafting monomer.
Canadian Patent 1,003,145 to Fournier et al., teaches a process of preparing graft polymers via a solu-tion polymerization in inert solvent wherein a resin-forming monomer is grafted to a rubbery copolymer of at least two alpha-monoolefins such as ethylene-propylene copolymers or ethylene-propylene diene terpolymers. The resin-forming monomer can be styrene, vinyl chloride, methyl methacrylate, or other monomers or mixed monomers.
The graft is isolated by precipitation with methanol, and is used as an impact modifier for certain plastics such a~ styrene-methyl styrene, styrene-methacrylic acid, styrene-methyl methacrylate and styrene-acrylonitrile.
Other prior art of interest are U.K. Patents 1,119,629 and 1,158,980.
~ . . . . . .
_3~ 81 SUMMARY OF THE INVENTION
An object of the present invention is to provide a process for producing weatherable, high-efficiency, easily compatibilized impact modifiers for PVC.
Another object is to provide novel PVC impact modi-fiers with improved properties.
A further object is to provide novel ~nd improved blends of PVC and certain impact modifiers.
These objects, and others which will become apparent from the following disclosure, are achieved by the present invention which in one aspect is a process for producing a polyvinvl chloride impact modifier comprising (a) introducing a polymer of ethylene exclusive of high density polyethylene, or a mixture of two or more of such polymers in a melt reactor which is capable of melt masticating a polymer, receiving and thoroughly mixing monomers and an initiator before and/or during the initiation of polymerization of said monomers, and removing excess monomer via a devolatilizing procedure; (b) introducing a monomer system comprising at least 50% by weight methyl methacrylate;
and (c) polymerizing said monomer system in the presence of a melt of said polymer at a temperature of from about 100C to 225C and about 0.01 to 4% by weight based on the monomer of an initiator so as to cause graft polymerization, but in the absence of a solvent which dissolves or swells said polymer.
DETAILED DESCRIPTION OF THE INVENTION
AND THE PREFERRED EMBODIMENTS
Ethylene polymers and mixtures of two or more such polymers which are normally incompatible with PVC by ordinary mixing techniques and because of this incompati-bility form polyblends with PVC which are non-uniform in appearance and non-resistant to impact can be compatibil-ized with PVC by grafting them with methyl methacrylate in a melt reaction to form polyblends which are highly impact resistant, and weather resistant as well.
Suitable ethylene polymers for melt reaction with MMA in the invention are ethylene-propylene copolymer (EP), ethylene-~inyl acetate copolymer (EVAc), ethylene-ethyl acrylate copolymer ~EEA), low density polyethylene (~DPE), ethylene-propylene-diene terpolymer (EPDM), and other polymers of ethylene, but exclusive of high density polyethylene ~HDPE). Mixtures of two or more such polymers are suitable. These copolymers are readily available as commercial products~
The monomer system comprising at least 50% by weight MMA can contain other vinyl monomers such as vinyl acetate, other methacrylates than the methyl ester, styrenes, Cl to C6 alkyl acrylates, acrylic and methacrylic acids, acrylo-nitriles, vinyl chloride, maleic anhydride and other copolymerizable vinyl monomers too numerous to mention.
The selection of comonomers is restricted, however, to the types and amounts which do not have negative impact modi-fication efficiency of the resultant graft polymers. One particular monomer system is a mixture of MMA and vinyl acetate in a 90/10 ratio, but all MMA is preferred from a convenience standpoint.
Any melt reactor device which is capable of melt masticating a polymer, receiving and thoroughly mixing monomers and an initiator before and/or during the initi-ation of polymerization of said monomers, and finally removing excess monomer via a devolatilizing procedure, is suitable. For example, an extruder, a sigma mixer, a Brabender, and the like can be used. However, an extruder has been found to be a highly preferred melt reactor device, and especially certain specific types of extruder reactors have been found to be advantageous. The most preferred type of extruder-reactor is the counter-rotating, tangential twin screw type having five zones: a polymer melt zone, a monomer addition zone, a separate initiator addition zone subsequent to the monomer addition zone, a separate reaction zone, and a separate devolatilization zone. It is preferable that the monomer addition zone be a flighted section wherein monomer addition takes place on full screws under full pressure, but not under high shear.
In accordance with a preferred method of the inven-tion, referring to the drawing which is a sectional :
i B
., . . . . . .. . , . . ; . . . ,.. ~ ., ., . . . .. .................. . ~ . .. .. .. . .
11~4~i81 elevational view of the extruder cavity but a side eleva-tional view of the extruder screw, polymer to be grafted is introduced to the extruder through a suitable feed port 11, melted and conveyed to the monomer addition zone 12 which is bounded on its proximal and distal ends by non-flighted tight fitting segments 18 and 19. Segments 19 may alternatively be flighted or even reverse flighted.
The constraints placed upon these screw segments which define the beginning and end of the monomer addition zone are only those which are necessary to effectively restrain the passage of monomer and polymer from the monomer addi-tion zone into the next extruder zone until said monomer and polymer are intimately mixed. Passing from the mono-mer addition zone 12, the monomer-polymer mix is conveyed into an initiator addition zone 20, the proximal and dis-tal ends of whic~, are bounded likewise by segments 19 and 25 which restrict movement of monomer/polymer and initi-ator until thorough and uniform blending of these materials has occurred. It is possible that some decomposition of initiator to radical fragments occurs in this zone, but the bulk of the reaction occurs in the next zone 22 which is the reaction zone, typically but not necessarily, the largest of the zones. This reaction zone is similarly bounded on its ends by tight-fitting sections 25 and 26 which prohibit back mixing into the preceding zone or escape of volatiles into the next zone 23 which serves as the devolatilization zone where excess monomer is removed through vacuum vent 14 so that the grafted product is obtained in strand form at the die 24 with no further purification step necessary.
The five-zone grafting extruder system described herein is a distinct improvement over the prior art systems, not only because of the significantly improved graft poly-mer impact modifiers produced thereby, but also because of safety advantages. Since the initiator never has access to large amounts of heated monomer, in the case of breakdown or power failure a runaway reaction is avoided.
Also, this invention precludes the danger of the monomer addition line being plugged via polymer formation in the addition line itself, at or near the addition port nozzle.
Another advantage is that once the mix of monomer, poly-mer, and initiator enters the reaction zone, the tempera-ture of the mix is high enough to produce extensive free-radical decomposition and commence grafting of monomer to polymer, assuring a uniform product.
The utility of this process is apparent in its superior performance in preparing grafted products which are both novel and efficient in imparting impact resis-tance to PVC.
Commercially available extrusion and injection molding grade ethylene polymers and copolymers are incom-patible with PVC by ordinary mixing techniques. Because of this incompatibility they form polyblends with PVC
which are non-uniform in appearance and non-resistant to impact. In accordance with this invention, said ethylene polymers and copolymers are compatibilized with PVC by grafting them with methyl methacrylate in a melt reaction.
Polyblends of PVC and the graft polymers are highly impact and weather resistant.
The following non-limiting examples are presented to illustrate a few embodiments of the invention. All parts and percentages are by weight unless otherwise indicated.
An ethylene-propylene ~EP) copolymer was fed at a rate of 25 g./minute into a counter rotating, tangential, twin screw extruder, having a cavity as illustrated in the drawing. The polymer was added at polymer addition port 11, and fluxed and conveyed across an ~nflighted tisht fitting compounding screw segment 16 into a monomer addition zone 12 bounded on its distal end by another ~ . . .
cylindrical compounding section 19. In this addition zone methyl methacrylate (uninhibited) was added @ 50 cc./min-ute) via addition port 15. Mixing of polymer and monomer occurred and the mixture passed over a cylindrical com-pounder 19 into an initiator mix zone 20 where initiatorin toluene solution ~25 9. 2,5-dimethyl-2,5-di-t-butyl-peroxy hexyne-3"(Lupersol 130)"diluted to 1 liter with toluene) was added via port 13 (@ 8 cc./minute). Mixing of the three components (polymer, monomer, and initiator solution) continued until the mix passed over a double compounding section 25 (cylindrical and double reverse compounders in tandem) , into a lengthy reaction zone 22 which itself contained many tight compounding sections designed ~i ~in these cases not to form separate and distinct additive/
mixing zones but rather to bring about continued and thorough mixing of the reactants throughout the reaction zone. The material finally passed into a devolatilizing zone 23 where excess volatiles were removed via port 14.
For every 100 9. of polymer fed to the extruder, 140 9.
of graft product was obtained at die 24. The temperature of reaction was set at 175C.
As in e~ple 1, replacing 100% EP polymer with a mix-ture (25/75! of EP/LDPE.
As in e~le 1, replacing 100% EP polymer with a mix-ture ~75/25) of EP/LDPE.
As in example 1, using ethylene vinyl acetate (9lE/9VA) in place of EP rubber.
EXAMPLE S
AS in example 1, substituting 100~ EP rubber with 75 parts EVA (9lE/9V~) and 25 parts EP.
35As in example 1, substitutinq 100% EP rubber with 25 parts EVA (glD/9VA) ~nd 75 parts EP.
* Trademark li~4~
As in example 1, replacing 100% EP copolymer with EVA
(95E/5VA).
As Ln ~ple 1, replacing 100~ EP copolymer with a blend of 75 parts LDPE and 25 parts EP.
As in example 1, replacing 100~ EP copolymer with a mixture of 25 parts LDPE and 75 parts EP.
To a three quart working capacity sigma mixern(Tele-dyne Readco)"whose temperature was controlled by a HAAKE**
circulating oil bath (set at 150C) was charged 1200 ~-of EP rubber. When the temperature of the muxer had reached 100C, 314 9. of MMA (un ~ ibited monomer) containing 8.6 9. of~upersol 130 ~as added all at once and the mixer sealed. The mixer was operated at 75 RPM's throughout the reaction procedure. The monomer/polymer mix was mas-ticated and well blended while the temperature of the reactor rose to 130C. At that time, 2.9 g. of t-butyl-peroctoate in 86 g. of MMA (uninhibited monomer) was added to the reaction chamber via a Lapp pump. Addition was complete in 14 minutes (toluene was used to clean the lines up to the reactor to assure-that all initiator solution was added to the reactor and no initiated monomer remained in the addition lines). A very rapid exotherm accompanied the addition of the low temperature initiator system. Peak temperature was 175C after about twenty minutes. One hundred minutes after add~tion was complete the reactor temperature was 155C. The reactor was evacuated to remove unreacted monomer. One tho~sand, five hundred and seven (1507) grams of polymer were obtained.
, .
* Trademark ** Tradbmark :: B
11~4~81 _9_ As in example 1, using an initiator solution containing l-octene as a grafting aid (25 9. of"Lupersol 130"plus 50 9. of l-octene diluted t.o 1 liter with toluene).
As in example 11 using a 95 parts MMA/5 parts hydroxy-ethylmethacrylate ~HEMA) monomer feed.
As in example 11 using a 90 parts MMA/10 parts vinyl acetate.
As m example 11 using ethylene-ethylacrylate as the grafting substrate.
As in example 1, using EPDM as the base polymer.
As in example 15, using 90 MMA/lOVAc as the monomer system.
As in example 1, using LDPE as the polymer, and MMA
as the grafting monomer.
i~ EXAMPLE 18 As in example 1, adding calcium carbonate filler to the polymer feed port 11 along with the base polymer.
EXAMPLE 19 ~Comparative) A solution grafted EP-g-MMA was made by charging 40 9. of the same EP as used in Example 1 into a pressure bomb along with 493 9. of benzene solvent sealed and heated to 90C to yield a cement. To this cement after cooling to room temperature was added 62.5 9. of MMA and 1.225 9. of di-t-butylperoxide. The bomb was resealed, stirred and heated to 125C overnight. The product graft ~ was precipitated in MeOH in a~Waring~lender; filter, con-I ~ centrated on a rotary evaporator and dried in a vacuum ~ 35 oven. The graft polymer produced was formulated with `~ PVC and compared with the analogous graft polymer of the : B * ~k '~
' , - ~ .
11 ~4~1 --1 o--invention. The results are reported in Example 22. The lower temperature impact efficiency of this comparative graft polymer prepared in accordance with the prior art was markedly lower.
As in Example 1 employing a 90 methyl methacrylate/10 maleic anhydride monomer mix, and an ethylene/ethyl acrylate feedstock polymer.
As m Example 1 using a 25 EP/75 EVA blend as the poly-mer feed.
Performance of Various Grafts in PVC
Graft Type (Example ~o.) Formulation Notched Izod Impact ft-lbs/in.
Room Temp. 16C
EP-g-MMA (1) 1 17 --EP-g-MMA (1) 2 25 --EP-g-MMA/VA (13) 1 18 --EPDM-g-MMA (15) 1 17 --EPDM-g-MMA/VA (16) 1 18 --EVA-g-MMA (7) 3 21 --EEA-g-MMA/MAH (20) 3 18 --LDPE-g-MMA (17) 4 21 --25EP/75LDPE-g-MMA (2) 4 21 __ 25EP/75EVA-g-MMA (21) 3 22 --Comparative (Extruder Graft vs. Solution Graft) EP-g-MMA (1) 3 24 22 EP-g-MMA (19) 3 23 14 Comparative (Ungrafted Polymer) EP 1 0.9 --EPDM 1 o.g __ ., ., B
-,~,,....................... , ~ . . , . . ... .. .. ~ .. ........ . .
11~4~81 Formulations (1) 100 PVC (K=69)/11 modifier/2.2 dibutyltin dioxide stabilizer.
BACKGROUND OF THE INV NTION
FIELD OF THE INVENTION
This invention relates to PVC impact modifiers, s their preparation, and use.
DESCRIPTION OF THE PRIOR ART
Conventional impact modifiers for PVC are multiple stage polymers having a butadiene or a methyl acrylate or ethyl acrylate first stage, and methyl methacrylate, acrylonitrile and/or styrene in one or more subsequent stages. U.S. Patents 2,892,809; 2,943,074; 3,251,904 are typical. Chlorinated polyethylene and ethylene-vinyl acetate have also been shown to be useful. See also Ency-clopedia of Polymer Science and Technology, under "Impact Resistance, PVC", and Plasty a Xaucuk 13, 129 and 193 (1976), and Plastics Technology, July 1975, page 48.
Each of these prior modifiers suffer from one or more disadvantages in the area of weatherability, ` impact efficiency, compoundability, processability into blends with PVC, and properties of blends with PVC.
, Steinkamp et al., U.S. Patent 3,862,265, show improvements to polyolefins in flow and adhesion by a controlled reaction often involving degradation in an extruder in which initiator is injected under conditions of either maximum distribution or intensive mixing wherein appreciable rheological, i.e. molecular weight distribu-tion, changes in said base polymer occur. In some ~ .
,s~ ~,, ~
11'~4~
embodiments monomers are also grafted during the degra-dation process. The extruder reactors shown by Steinkamp et al., have a first polymer addition and melting zone, a second zone for monomer and initiator addition and reaction, and a third zone for vacuum devolatilization and extrusion or removal of product. In the second zone, the mixing is under high intensity in a very short period of time. Materials can be added prior to the reaction zone, become mixed by extruder action, and thence con-veyed to the reaction zone where they are available toparticipate in the reaction. Steinkamp et al., does not show graft polymers which are useful as impact modi-fiers for PVC.
Nowak et al., U.S. Patent 3,177,269, teach an extruder grafting process using an olefinic polymer sub-strate and grafting thereto acrylic acid, methacrylic acids, or mixtures thereof. The graft polymer is recovered by use of an inert solvent, and is used as a molding resin.
Jones et al., U.S. Patent 3,177,270, teach a process similar to Nowak et al., supra, except using monovinyl aromatic compounds as the grafting monomer.
Canadian Patent 1,003,145 to Fournier et al., teaches a process of preparing graft polymers via a solu-tion polymerization in inert solvent wherein a resin-forming monomer is grafted to a rubbery copolymer of at least two alpha-monoolefins such as ethylene-propylene copolymers or ethylene-propylene diene terpolymers. The resin-forming monomer can be styrene, vinyl chloride, methyl methacrylate, or other monomers or mixed monomers.
The graft is isolated by precipitation with methanol, and is used as an impact modifier for certain plastics such a~ styrene-methyl styrene, styrene-methacrylic acid, styrene-methyl methacrylate and styrene-acrylonitrile.
Other prior art of interest are U.K. Patents 1,119,629 and 1,158,980.
~ . . . . . .
_3~ 81 SUMMARY OF THE INVENTION
An object of the present invention is to provide a process for producing weatherable, high-efficiency, easily compatibilized impact modifiers for PVC.
Another object is to provide novel PVC impact modi-fiers with improved properties.
A further object is to provide novel ~nd improved blends of PVC and certain impact modifiers.
These objects, and others which will become apparent from the following disclosure, are achieved by the present invention which in one aspect is a process for producing a polyvinvl chloride impact modifier comprising (a) introducing a polymer of ethylene exclusive of high density polyethylene, or a mixture of two or more of such polymers in a melt reactor which is capable of melt masticating a polymer, receiving and thoroughly mixing monomers and an initiator before and/or during the initiation of polymerization of said monomers, and removing excess monomer via a devolatilizing procedure; (b) introducing a monomer system comprising at least 50% by weight methyl methacrylate;
and (c) polymerizing said monomer system in the presence of a melt of said polymer at a temperature of from about 100C to 225C and about 0.01 to 4% by weight based on the monomer of an initiator so as to cause graft polymerization, but in the absence of a solvent which dissolves or swells said polymer.
DETAILED DESCRIPTION OF THE INVENTION
AND THE PREFERRED EMBODIMENTS
Ethylene polymers and mixtures of two or more such polymers which are normally incompatible with PVC by ordinary mixing techniques and because of this incompati-bility form polyblends with PVC which are non-uniform in appearance and non-resistant to impact can be compatibil-ized with PVC by grafting them with methyl methacrylate in a melt reaction to form polyblends which are highly impact resistant, and weather resistant as well.
Suitable ethylene polymers for melt reaction with MMA in the invention are ethylene-propylene copolymer (EP), ethylene-~inyl acetate copolymer (EVAc), ethylene-ethyl acrylate copolymer ~EEA), low density polyethylene (~DPE), ethylene-propylene-diene terpolymer (EPDM), and other polymers of ethylene, but exclusive of high density polyethylene ~HDPE). Mixtures of two or more such polymers are suitable. These copolymers are readily available as commercial products~
The monomer system comprising at least 50% by weight MMA can contain other vinyl monomers such as vinyl acetate, other methacrylates than the methyl ester, styrenes, Cl to C6 alkyl acrylates, acrylic and methacrylic acids, acrylo-nitriles, vinyl chloride, maleic anhydride and other copolymerizable vinyl monomers too numerous to mention.
The selection of comonomers is restricted, however, to the types and amounts which do not have negative impact modi-fication efficiency of the resultant graft polymers. One particular monomer system is a mixture of MMA and vinyl acetate in a 90/10 ratio, but all MMA is preferred from a convenience standpoint.
Any melt reactor device which is capable of melt masticating a polymer, receiving and thoroughly mixing monomers and an initiator before and/or during the initi-ation of polymerization of said monomers, and finally removing excess monomer via a devolatilizing procedure, is suitable. For example, an extruder, a sigma mixer, a Brabender, and the like can be used. However, an extruder has been found to be a highly preferred melt reactor device, and especially certain specific types of extruder reactors have been found to be advantageous. The most preferred type of extruder-reactor is the counter-rotating, tangential twin screw type having five zones: a polymer melt zone, a monomer addition zone, a separate initiator addition zone subsequent to the monomer addition zone, a separate reaction zone, and a separate devolatilization zone. It is preferable that the monomer addition zone be a flighted section wherein monomer addition takes place on full screws under full pressure, but not under high shear.
In accordance with a preferred method of the inven-tion, referring to the drawing which is a sectional :
i B
., . . . . . .. . , . . ; . . . ,.. ~ ., ., . . . .. .................. . ~ . .. .. .. . .
11~4~i81 elevational view of the extruder cavity but a side eleva-tional view of the extruder screw, polymer to be grafted is introduced to the extruder through a suitable feed port 11, melted and conveyed to the monomer addition zone 12 which is bounded on its proximal and distal ends by non-flighted tight fitting segments 18 and 19. Segments 19 may alternatively be flighted or even reverse flighted.
The constraints placed upon these screw segments which define the beginning and end of the monomer addition zone are only those which are necessary to effectively restrain the passage of monomer and polymer from the monomer addi-tion zone into the next extruder zone until said monomer and polymer are intimately mixed. Passing from the mono-mer addition zone 12, the monomer-polymer mix is conveyed into an initiator addition zone 20, the proximal and dis-tal ends of whic~, are bounded likewise by segments 19 and 25 which restrict movement of monomer/polymer and initi-ator until thorough and uniform blending of these materials has occurred. It is possible that some decomposition of initiator to radical fragments occurs in this zone, but the bulk of the reaction occurs in the next zone 22 which is the reaction zone, typically but not necessarily, the largest of the zones. This reaction zone is similarly bounded on its ends by tight-fitting sections 25 and 26 which prohibit back mixing into the preceding zone or escape of volatiles into the next zone 23 which serves as the devolatilization zone where excess monomer is removed through vacuum vent 14 so that the grafted product is obtained in strand form at the die 24 with no further purification step necessary.
The five-zone grafting extruder system described herein is a distinct improvement over the prior art systems, not only because of the significantly improved graft poly-mer impact modifiers produced thereby, but also because of safety advantages. Since the initiator never has access to large amounts of heated monomer, in the case of breakdown or power failure a runaway reaction is avoided.
Also, this invention precludes the danger of the monomer addition line being plugged via polymer formation in the addition line itself, at or near the addition port nozzle.
Another advantage is that once the mix of monomer, poly-mer, and initiator enters the reaction zone, the tempera-ture of the mix is high enough to produce extensive free-radical decomposition and commence grafting of monomer to polymer, assuring a uniform product.
The utility of this process is apparent in its superior performance in preparing grafted products which are both novel and efficient in imparting impact resis-tance to PVC.
Commercially available extrusion and injection molding grade ethylene polymers and copolymers are incom-patible with PVC by ordinary mixing techniques. Because of this incompatibility they form polyblends with PVC
which are non-uniform in appearance and non-resistant to impact. In accordance with this invention, said ethylene polymers and copolymers are compatibilized with PVC by grafting them with methyl methacrylate in a melt reaction.
Polyblends of PVC and the graft polymers are highly impact and weather resistant.
The following non-limiting examples are presented to illustrate a few embodiments of the invention. All parts and percentages are by weight unless otherwise indicated.
An ethylene-propylene ~EP) copolymer was fed at a rate of 25 g./minute into a counter rotating, tangential, twin screw extruder, having a cavity as illustrated in the drawing. The polymer was added at polymer addition port 11, and fluxed and conveyed across an ~nflighted tisht fitting compounding screw segment 16 into a monomer addition zone 12 bounded on its distal end by another ~ . . .
cylindrical compounding section 19. In this addition zone methyl methacrylate (uninhibited) was added @ 50 cc./min-ute) via addition port 15. Mixing of polymer and monomer occurred and the mixture passed over a cylindrical com-pounder 19 into an initiator mix zone 20 where initiatorin toluene solution ~25 9. 2,5-dimethyl-2,5-di-t-butyl-peroxy hexyne-3"(Lupersol 130)"diluted to 1 liter with toluene) was added via port 13 (@ 8 cc./minute). Mixing of the three components (polymer, monomer, and initiator solution) continued until the mix passed over a double compounding section 25 (cylindrical and double reverse compounders in tandem) , into a lengthy reaction zone 22 which itself contained many tight compounding sections designed ~i ~in these cases not to form separate and distinct additive/
mixing zones but rather to bring about continued and thorough mixing of the reactants throughout the reaction zone. The material finally passed into a devolatilizing zone 23 where excess volatiles were removed via port 14.
For every 100 9. of polymer fed to the extruder, 140 9.
of graft product was obtained at die 24. The temperature of reaction was set at 175C.
As in e~ple 1, replacing 100% EP polymer with a mix-ture (25/75! of EP/LDPE.
As in e~le 1, replacing 100% EP polymer with a mix-ture ~75/25) of EP/LDPE.
As in example 1, using ethylene vinyl acetate (9lE/9VA) in place of EP rubber.
EXAMPLE S
AS in example 1, substituting 100~ EP rubber with 75 parts EVA (9lE/9V~) and 25 parts EP.
35As in example 1, substitutinq 100% EP rubber with 25 parts EVA (glD/9VA) ~nd 75 parts EP.
* Trademark li~4~
As in example 1, replacing 100% EP copolymer with EVA
(95E/5VA).
As Ln ~ple 1, replacing 100~ EP copolymer with a blend of 75 parts LDPE and 25 parts EP.
As in example 1, replacing 100~ EP copolymer with a mixture of 25 parts LDPE and 75 parts EP.
To a three quart working capacity sigma mixern(Tele-dyne Readco)"whose temperature was controlled by a HAAKE**
circulating oil bath (set at 150C) was charged 1200 ~-of EP rubber. When the temperature of the muxer had reached 100C, 314 9. of MMA (un ~ ibited monomer) containing 8.6 9. of~upersol 130 ~as added all at once and the mixer sealed. The mixer was operated at 75 RPM's throughout the reaction procedure. The monomer/polymer mix was mas-ticated and well blended while the temperature of the reactor rose to 130C. At that time, 2.9 g. of t-butyl-peroctoate in 86 g. of MMA (uninhibited monomer) was added to the reaction chamber via a Lapp pump. Addition was complete in 14 minutes (toluene was used to clean the lines up to the reactor to assure-that all initiator solution was added to the reactor and no initiated monomer remained in the addition lines). A very rapid exotherm accompanied the addition of the low temperature initiator system. Peak temperature was 175C after about twenty minutes. One hundred minutes after add~tion was complete the reactor temperature was 155C. The reactor was evacuated to remove unreacted monomer. One tho~sand, five hundred and seven (1507) grams of polymer were obtained.
, .
* Trademark ** Tradbmark :: B
11~4~81 _9_ As in example 1, using an initiator solution containing l-octene as a grafting aid (25 9. of"Lupersol 130"plus 50 9. of l-octene diluted t.o 1 liter with toluene).
As in example 11 using a 95 parts MMA/5 parts hydroxy-ethylmethacrylate ~HEMA) monomer feed.
As in example 11 using a 90 parts MMA/10 parts vinyl acetate.
As m example 11 using ethylene-ethylacrylate as the grafting substrate.
As in example 1, using EPDM as the base polymer.
As in example 15, using 90 MMA/lOVAc as the monomer system.
As in example 1, using LDPE as the polymer, and MMA
as the grafting monomer.
i~ EXAMPLE 18 As in example 1, adding calcium carbonate filler to the polymer feed port 11 along with the base polymer.
EXAMPLE 19 ~Comparative) A solution grafted EP-g-MMA was made by charging 40 9. of the same EP as used in Example 1 into a pressure bomb along with 493 9. of benzene solvent sealed and heated to 90C to yield a cement. To this cement after cooling to room temperature was added 62.5 9. of MMA and 1.225 9. of di-t-butylperoxide. The bomb was resealed, stirred and heated to 125C overnight. The product graft ~ was precipitated in MeOH in a~Waring~lender; filter, con-I ~ centrated on a rotary evaporator and dried in a vacuum ~ 35 oven. The graft polymer produced was formulated with `~ PVC and compared with the analogous graft polymer of the : B * ~k '~
' , - ~ .
11 ~4~1 --1 o--invention. The results are reported in Example 22. The lower temperature impact efficiency of this comparative graft polymer prepared in accordance with the prior art was markedly lower.
As in Example 1 employing a 90 methyl methacrylate/10 maleic anhydride monomer mix, and an ethylene/ethyl acrylate feedstock polymer.
As m Example 1 using a 25 EP/75 EVA blend as the poly-mer feed.
Performance of Various Grafts in PVC
Graft Type (Example ~o.) Formulation Notched Izod Impact ft-lbs/in.
Room Temp. 16C
EP-g-MMA (1) 1 17 --EP-g-MMA (1) 2 25 --EP-g-MMA/VA (13) 1 18 --EPDM-g-MMA (15) 1 17 --EPDM-g-MMA/VA (16) 1 18 --EVA-g-MMA (7) 3 21 --EEA-g-MMA/MAH (20) 3 18 --LDPE-g-MMA (17) 4 21 --25EP/75LDPE-g-MMA (2) 4 21 __ 25EP/75EVA-g-MMA (21) 3 22 --Comparative (Extruder Graft vs. Solution Graft) EP-g-MMA (1) 3 24 22 EP-g-MMA (19) 3 23 14 Comparative (Ungrafted Polymer) EP 1 0.9 --EPDM 1 o.g __ ., ., B
-,~,,....................... , ~ . . , . . ... .. .. ~ .. ........ . .
11~4~81 Formulations (1) 100 PVC (K=69)/11 modifier/2.2 dibutyltin dioxide stabilizer.
(2) 100 PVC (K=69)/7 modifier/2 lubricating process-ing aid/2 stabilizer.
(3) 100 PVC (K=69)/8 modifier/2.4 acrylic process-ing aid/0.4 lubricant/l ethylene bis stearamide/2 dibutyl-tin dioxide stabilizer/10 TiO2.
(4) 100 PVC (K=69)/4 modifier/2.4 acrylic process-ing aid/0.9 lubricant/l ethylene bis stearamide/14 TiO2/2 dibutyltin dioxide stabilizer.
~, . ..
~, . ..
Claims (8)
1. A process for producing a polyvinyl chloride impact modifier comprising (a) introducing a polymer of ethylene exclusive of high density polyethylene, or a mixture of two or more of such polymers in a melt reactor which is capable of melt masticating a polymer, receiving and thoroughly mixing monomers and an initiator before and/or during the initiation of polymerization of said monomers, and removing excess monomer via a devolatilizing procedure; (b) introducing a monomer system comprising at least 50% by weight methyl meth-acrylate; and (c) polymerizing said monomer system in the presence of a melt of said polymer at a temperature of from about 100°C to 225°C and about 0.01 to 4% by weight based on the monomer of an initiator so as to cause graft polymerization, but in the absence of a solvent which dissolves or swells said polymer.
2. Process of claim 1 wherein said polymer of ethylene or mixture of two or more such polymers is selected from the group consisting of ethylene-propylene copolymer, ethylene-propylene-diene terpolymer, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and a mixture of ethylene-propylene copolymer and low density polyethylene polymer.
3. Process of claim 1 wherein said melt reactor is an extruder reactor.
4. Process of claim 3 wherein said extruder reactor is a twin screw counter-rotating, tangential type having a monomer addition zone, a separate initiator addition zone subsequent to said monomer addition zone, and a separate reaction zone.
5. A process of claim 4 wherein said monomer addi-tion zone is a flighted section and is one wherein monomer addition takes place on full screws under full pressure, but not under high shear.
6. Process of claim 1 wherein the ratio of monomer system to polymer is about 5:95 to about 50:50 by weight.
7. Process of claim 1 wherein said initiator is 2,5-dimethyl-2,5-di-t-butoxyhexyne-3.
8. Process of claim 1 wherein said polymerization is conducted at about 150°C to 200°C.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US11447880A | 1980-01-23 | 1980-01-23 | |
| US114,478 | 1980-01-23 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1144681A true CA1144681A (en) | 1983-04-12 |
Family
ID=22355463
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000368891A Expired CA1144681A (en) | 1980-01-23 | 1981-01-20 | Extruder grafting process for pvc impact modifier |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0033220B1 (en) |
| JP (1) | JPS56109240A (en) |
| CA (1) | CA1144681A (en) |
| DE (1) | DE3163016D1 (en) |
| ES (2) | ES8307847A1 (en) |
| ZA (1) | ZA81322B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4857254A (en) * | 1988-02-22 | 1989-08-15 | Du Pont Canada Inc. | Method for grafting monomers onto molten hydrocarbon polymer |
Families Citing this family (23)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58109505A (en) * | 1981-12-21 | 1983-06-29 | イ−・アイ・デユポン・デ・ニモアス・アンド・カンパニ− | Extruder process for manufacturing functionated polyolefin polymer |
| AU1199683A (en) * | 1982-03-11 | 1983-09-15 | Uniroyal Inc. | Graft copolymer and pvc resin blend |
| US4476283A (en) * | 1982-11-12 | 1984-10-09 | Uniroyal, Inc. | Graft copolymerization process |
| USRE32217E (en) * | 1982-11-12 | 1986-07-29 | The Dow Chemical Company | Graft copolymerization process |
| JPS6116949A (en) * | 1984-07-03 | 1986-01-24 | Dainippon Ink & Chem Inc | Vinyl chloride resin composition |
| CA1236613A (en) * | 1985-06-27 | 1988-05-10 | Chun S. Wong | Process for the grafting of monomers onto polyolefins |
| US5229456A (en) * | 1988-03-29 | 1993-07-20 | Rohm And Haas Company | Graft copolymers and blends thereof with polyolefins |
| US5300570A (en) * | 1989-03-01 | 1994-04-05 | Rohm And Haas Company | Plastic articles with compatibilized barrier resin |
| US4957974A (en) * | 1988-03-29 | 1990-09-18 | Rohm And Haas Company | Graft copolymers and blends thereof with polyolefins |
| BE1003120A5 (en) * | 1988-03-29 | 1991-12-03 | Rohm & Haas | GRAFT COPOLYMERS, PROCESS FOR THEIR PREPARATION, PROCESS USING THEM TO IMPROVE POLYOLEFINS AND MIXTURES AND PRODUCTS CONTAINING SAME WITH POLYOLEFINS. |
| US5196483A (en) * | 1988-07-18 | 1993-03-23 | American Cyanamid Company | Rubber compositions with a high elastic modulus |
| EP0451310A1 (en) * | 1990-04-10 | 1991-10-16 | Röhm Gmbh | Modified rubber compositions for reinforcing polyacrylate products |
| WO1991016189A1 (en) * | 1990-04-12 | 1991-10-31 | Exxon Chemical Patents Inc. | Polymer grafting process, apparatus and products obtained therewith |
| EP0560496A1 (en) * | 1992-02-24 | 1993-09-15 | Rohm And Haas Company | Processing of polar polymers and mixtures obtained thereby |
| DE69521808T2 (en) * | 1994-08-25 | 2001-11-08 | Eastman Chemical Co., Kingsport | MALEINIZED POLYPROPYLENE WITH HIGH ACID NUMBER, HIGH MOLECULAR WEIGHT AND LOW COLOR |
| FR2743746B1 (en) | 1996-01-23 | 1998-04-03 | Atochem Elf Sa | NEW RELEASE FILM FOR SHEET MOLDING COMPOUNDING PRODUCT |
| DE19641954A1 (en) * | 1996-10-11 | 1998-04-16 | Rohmax Additives Gmbh | New polymer in polymer dispersion as a VI improver |
| WO2003072644A2 (en) | 2002-02-22 | 2003-09-04 | Dow Global Technologies Inc. | Thermoplastic foam containing particulate additive |
| CN101838362B (en) | 2002-10-15 | 2012-11-28 | 埃克森美孚化学专利公司 | Polyolefin adhesive compositions and articles made therefrom |
| US7700707B2 (en) | 2002-10-15 | 2010-04-20 | Exxonmobil Chemical Patents Inc. | Polyolefin adhesive compositions and articles made therefrom |
| ITTO20070125A1 (en) * | 2007-02-21 | 2008-08-22 | F Lli Maris S P A | PROCEDURE FOR CONDUCTING A CHEMICAL REACTION IN THE LIQUID PHASE WITHIN A BIVITE EXTRUDER. |
| US9713893B2 (en) * | 2013-07-09 | 2017-07-25 | Wenger Manufacturing, Inc. | Method of preconditioning comestible materials using steam/water static mixer |
| FR3060570A1 (en) * | 2016-12-19 | 2018-06-22 | Compagnie Generale Des Etablissements Michelin | PROCESS FOR THE PREPARATION OF A DIODE MODEL ELASTOMER MODIFIED BY A 1,3-DIPOLAR COMPOUND BY REACTIVE EXTRUSION |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL101818C (en) * | 1955-05-18 | 1900-01-01 | ||
| US3177270A (en) * | 1960-10-10 | 1965-04-06 | Dow Chemical Co | Graft copolymers of polyolefins and monovinyl aromatic compounds and method of making the same |
| NL128227C (en) * | 1963-09-20 | 1900-01-01 | ||
| FR1494634A (en) * | 1965-09-29 | 1967-09-08 | Goodrich Co B F | Graft-modified ethylene-propylene and ethylene-propylene-diene polymers |
| US3622652A (en) * | 1967-12-19 | 1971-11-23 | Goodrich Co B F | Epdm polymers modified by graft polymerization |
| NL163235C (en) * | 1970-10-27 | 1980-08-15 | Japan Synthetic Rubber Co Ltd | METHOD FOR PREPARING AN IMPACT RESIN, AND ARTICLES FORMED THEREFROM |
| US3862265A (en) * | 1971-04-09 | 1975-01-21 | Exxon Research Engineering Co | Polymers with improved properties and process therefor |
| US4026967A (en) * | 1976-06-25 | 1977-05-31 | E. I. Du Pont De Nemours And Company | Process for making grafted polymeric material |
-
1981
- 1981-01-19 ZA ZA00810322A patent/ZA81322B/en unknown
- 1981-01-20 CA CA000368891A patent/CA1144681A/en not_active Expired
- 1981-01-21 EP EP81300266A patent/EP0033220B1/en not_active Expired
- 1981-01-21 DE DE8181300266T patent/DE3163016D1/en not_active Expired
- 1981-01-22 JP JP731881A patent/JPS56109240A/en active Pending
- 1981-01-23 ES ES499383A patent/ES8307847A1/en not_active Expired
-
1982
- 1982-02-04 ES ES509318A patent/ES509318A0/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4857254A (en) * | 1988-02-22 | 1989-08-15 | Du Pont Canada Inc. | Method for grafting monomers onto molten hydrocarbon polymer |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0033220A3 (en) | 1982-01-06 |
| DE3163016D1 (en) | 1984-05-17 |
| ZA81322B (en) | 1982-03-31 |
| ES8305595A1 (en) | 1983-05-16 |
| ES509318A0 (en) | 1983-05-16 |
| ES499383A0 (en) | 1983-08-16 |
| EP0033220A2 (en) | 1981-08-05 |
| JPS56109240A (en) | 1981-08-29 |
| ES8307847A1 (en) | 1983-08-16 |
| EP0033220B1 (en) | 1984-04-11 |
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